Sewage analysis as an alternative tool for assessing drug of abuse and new psychoactive substances in Tunisia.

Many studies attest to the pollution of wastewaters by organic molecules including drug of abuse (DAs) residues and new psychoactive substances (NPS) at trace levels. The occurrence of these emerging micropollutants in influent wastewaters (IWW) from three Tunisian Wastewater Treatment Plants (WWTPs) was assessed. Influent wastewater composite samples (24 h) were collected over 7 consecutive days in November 2019. The determination and quantification of 11 drug of abuse or their metabolites was performed by the application of an optimized multi-residue method liquid chromatography tandem mass spectrometry (LC-MS/MS). MDMA, THC and the cocaine metabolite benzoyl ecgonine were the most detected substances across the three investigated sewage plants. A new wastewater-based epidemiology (WBE) approach was applied in this study to estimate illicit drug consumption. This innovative approach was used to calculate and to assess collective drug consumption of illicit drug at a community level, based on the concentration of selected illicit substances and their major metabolites in influent wastewater. The average MDMA consumption found in the selected cities ranged between 35,8-1531,1 mg day- 1/1000 inhabitants and increased during the weekends. Cocaine consumption varied from 24.5 to 179.8 mg day- 1/1000 inhabitants. Complementary qualitative investigation of new psychoactive substances was monitored for the first time for an African country, examining the occurrence of 33 NPS in wastewaters samples. Out of 33 totals screened NPS across all sampling sites, 16 were tentatively identified with this approach. The 16 detected NPS covered most of the representative and used molecules of different NPS classes; including synthetic opioids, synthetic cathinones, amphetamines derivatives and synthetic cannabinoids.

Illicit substances identified in the urine of 11.170 suspected drug users in North Tunisia.

INTRODUCTION: according to the latest World Drug Report, 271 million people worldwide (5.5% of the global population) aged 15-64 years are drug users. Drug addiction and trafficking became an urgent public health problem that affects human health and social life. A cross-sectional study was conducted from January 2016 to December 2018, to identify the socio-demographic profile of drug users captured by the anti-narcotics squad in North of Tunisia (North African country) and to type, through toxicological analysis, the nature of the substances consumed. METHODS: data were collected from expertise files of 11170 suspected drug users. Fresh urine samples were collected from suspected drugs users and submitted in the toxicology laboratory of the center for Urgent Medical Assistance (Tunis) for forensic urinalysis. Drugs screening was carried out by immunochemical methods. Positive samples were analyzed with gas chromatography coupled to mass selective detector (GC-MS) for confirmation. RESULTS: the investigation revealed that drug users were mainly males 97.4% (sex ratio 37), the median age was 29 ± 7.91 years, 91.3% were singles and 79% were daily workers. On a total of 11170 urine samples screened, 5 409 (48.4%) were positives for illicit drugs. The prevalence of positive samples was 55.4% in 2016; 50.45% in 2017 and 40.8% in 2018. Cannabis was the most widely consumed drug (95%), followed by Benzodiazepines (1.2%), Buprenorphine (1%), cocaine (0.95%), MDMA (0.24%) and opiates (0.13%). Polydrug abuse was observed in 79 specimens (1.5%). CONCLUSION: this study provides an overview of the illicit drug consumption in the north of Tunisia (knowing that nowadays epidemiological data are almost same since 2016) in order to set up an effective policy to fight against drugs and addictive behaviors and to provide health professionals with the epidemiological elements necessary for better medical care of drug users.

Pharmaceuticals and illicit drugs in wastewater samples in north-eastern Tunisia.

Pharmaceutically active substances (PhACs) and drugs of abuse (DAs) are two classes of contaminants of emerging concern that have attracted great concern and interest by the scientific community during the last two decades. Numerous studies have revealed their presence in treated urban wastewaters. This is mainly due to the fact that some compounds are not efficiently removed during wastewater treatment processes, and are thus able to reach the aquatic environment through wastewater discharge and reuse practices. The application of an optimized multi-residue method for the simultaneous confirmation and quantification of licit and illicit drugs has been investigated in influent and effluent wastewater samples from seven wastewater treatment plants (WWTPs) located in north-eastern Tunisia. Analysis was performed through ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Out of 12 pharmaceutical compounds analyzed, 11 of them were detected mainly in effluent wastewaters. In both matrices, antibiotics and ß-blockers were the most detected groups. This suggests that these compounds show noticeable resistance against biological treatment in WWTPs. The estimated concentrations of antibiotics in effluents ranged from ca. 35 ng/L to 1.2 µg/L. However, all five studied illicit drugs were detected, mainly in influent wastewaters. Forensic investigation performed on people suspected to be drug abusers covering all Tunisian cities was conducted by monitoring an epidemiological study of human urine samples surveying rate of consumption for illicit drugs. Hence, these preliminary results confirmed the presence of illicit drugs in the influent wastewater samples. For example, quantification ranges for cocaine were found to be 25-450 ng/L in influent wastewater samples. Significant differences for cocaine consumption across the two sampling methods were observed. Consequently, we conclude that the analyses in wastewater are more reflective of the real levels of illicit drug consumption. Moreover, the cost for chromatographic analysis is lower than the screening test methods for human biological specimen, particularly staffing, which are likely to be much lower.